+#define USE_CORRECT_PAL_TIMINGS
+// A lot of confusion comes from here...
+// The thing to keep in mind is that the VC is advanced every HALF line, regardless
+// of whether the display is interlaced or not. The only difference with an
+// interlaced display is that the high bit of VC will be set when the lower
+// field is being rendered. (NB: The high bit of VC is ALWAYS set on the lower field,
+// regardless of whether it's in interlace mode or not.
+// NB2: Seems it doens't always, not sure what the constraint is...)
+//
+// Normally, TVs will render a full frame in 1/30s (NTSC) or 1/25s (PAL) by
+// rendering two fields that are slighty vertically offset from each other.
+// Each field is created in 1/60s (NTSC) or 1/50s (PAL), and every other line
+// is rendered in this mode so that each field, when overlaid on each other,
+// will yield the final picture at the full resolution for the full frame.
+//
+// We execute a half frame in each timeslice (1/60s NTSC, 1/50s PAL).
+// Since the number of lines in a FULL frame is 525 for NTSC, 625 for PAL,
+// it will be half this number for a half frame. BUT, since we're counting
+// HALF lines, we double this number and we're back at 525 for NTSC, 625 for PAL.
+//
+// Scanline times are 63.5555... µs in NTSC and 64 µs in PAL
+// Half line times are, naturally, half of this. :-P
+void HalflineCallback(void)